Const
Ref: https://github.com/paritytech/polkadot-sdk/blob/bc53b9a03a742f8b658806a01a7bf853cb9a86cd/substrate/primitives/transaction-pool/src/runtime_api.rs#L25-L30
Ref: https://github.com/paritytech/polkadot-sdk/blob/bc53b9a03a742f8b658806a01a7bf853cb9a86cd/substrate/primitives/transaction-pool/src/runtime_api.rs#L25-L30